Neurology

DDT: Pesticide linked to Alzheimer’s

Exposure to a once widely used pesticide, DDT, may increase the chances of developing Alzheimer’s disease, suggest US researchers.

A study, published in JAMA Neurology, showed patients with Alzheimer’s had four times the levels of DDT lingering in the body than healthy people.

Some countries still use the pesticide to control malaria.

Alzheimer’s Research UK said more evidence was needed to prove DDT had a role in dementia.

DDT was a massively successful pesticide, initially used to control malaria at the end of World War Two and then to protect crops in commercial agriculture.

However, there were questions about its impact on human health and wider environmental concerns, particularly for predators.

It was banned in the US in 1972 and in many other countries. But the World Health Organization still recommends using DDT to keep malaria in check.

Not clear
DDT also lingers in the human body where it is broken down into DDE.

The team at Rutgers University and Emory University tested levels of DDE in the blood of 86 people with Alzheimer’s disease and compared the results with 79 healthy people of a similar age and background.

The results showed those with Alzheimer’s had 3.8 times the level of DDE.

However, the picture is not clear-cut. Some healthy people had high levels of DDE while some with Alzheimer’s had low levels. Alzheimer’s also predates the use of DDT.

The researchers believe the chemical is increasing the chance of Alzheimer’s and may be involved in the development of amyloid plaques in the brain, a hallmark of the disease, which contribute to the death of brain cells.

Prof Allan Levey, the director of the Alzheimer’s Disease Research Centre at Emory, said: “This is one of the first studies identifying a strong environmental risk factor for Alzheimer’s disease.

“The magnitude of the effect is strikingly large, it is comparable in size to the most common genetic risk factor for late-onset Alzheimer’s.”

Fellow researcher Dr Jason Richardson added: “We are still being exposed to these chemicals in the United States, both because we get food products from other countries and because DDE persists in the environment for a long time,” .

Dr Simon Ridley, the head of research at the charity Alzheimer’s Research UK, said: “It’s important to note that this research relates to DDT, a pesticide that has not been used in the UK since the 1980s.

“While this small study suggests a possible connection between DDT exposure and Alzheimer’s, we don’t know whether other factors may account for these results.

“Much more research would be needed to confirm whether this particular pesticide may contribute to the disease.”

Source; BBC news

Alzheimer’s disease could soon become history

Researchers from the Yale University School of Medicine have found a protein that is the missing link in the complicated chain of events that lead to Alzheimer`s disease.

Researchers also found that blocking the protein with an existing drug can restore memory in mice with brain damage that mimics the disease.

Stephen Strittmatter, the Vincent Coates Professor of Neurology and senior author of the study, said that the new discovery has given them hope that they e can find a drug that is going to work to lessen the burden of Alzheimer`s.

In earlier work, Strittmatter`s lab showed that the amyloid-beta peptides, which are a hallmark of Alzheimer`s, couple with prion proteins on the surface of neurons. By an unknown process, the coupling activates a molecular messenger within the cell called Fyn.

In the new study, the team revealed the missing link in the chain, a protein within the cell membrane called metabotropic glutamate receptor 5 or mGluR5.

When the protein is blocked by a drug similar to one being developed for Fragile X syndrome, the deficits in memory, learning, and synapse density were restored in a mouse model of Alzheimer`s.

The findings have been reported in the journal Neuron.

 

Early diagnostic tool for Alzheimer’s comes closer to reality

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Researchers have made a new breakthrough which may not only help diagnose Alzheimer`s, but also assess its severity

Researchers have made a new breakthrough which may not only help diagnose Alzheimer`s, but also assess its severity.

Patients with Alzheimer`s disease currently undergo neuropsychological testing to detect signs of the disease. The test results are difficult to interpret and are insufficient for making a definitive diagnosis.

But as scientists have already discovered, activity in certain areas of the cerebral cortex is affected even in the early stages of the disease. Professor Tiago H. Falk of INRS`s Centre Energie Materiaux Telecommunications, specializing in biological signal acquisition, examined this phenomenon and compared the electroencephalograms (EEGs) of healthy individuals (27), individuals with mild Alzheimer`s (27), and individuals with moderate cases of the disease (22).

He found statistically significant differences across the three groups.

In collaboration with neurologists and Francisco J. Fraga, an INRS visiting professor specializing in biological signals, Professor Falk used an algorithm that dissects brain waves of varying frequencies.

Falk said that what makes this algorithm innovative is that it characterizes the changes in temporal dynamics of the patients` brain waves.

He asserted that the findings show that healthy individuals have different patterns than those with mild Alzheimer`s disease and asserted that they also found a difference between patients with mild levels of the disease and those with moderate Alzheimer`s.

The study has been published in the journal PLOS ONE.